1. Field of the Invention
The present invention relates to the conversion of the kinetic energy in a moving fluid to rotational mechanical energy and more particularly to a wind driven apparatus for the generation of electricity, pumping water, or other purposes.
2. General Background
There exist numerous examples of fluid or wind driven machinery that convert kinetic energy into mechanical energy and more particularly into the rotation of a shaft or turbine. Each of these machines accomplish their intended purpose by directing the wind or the fluid against a collector causing it to rotate thereby creating the desired mechanical energy.
All such machines may be categorized differently. They may be grouped as to whether the axis of rotation of the collector is horizontal or vertical. Additionally, the rotor blades or vanes of the collector may be of the `open` or `closed` variety. The `open` or squirrel cage variety enables the wind to flow around and past the vanes in the manner of an air foil. They rely upon aerodynamic lift to cause rotation. Conversly, `closed` type rotor blades rely upon the direct impact of the force of the wind on the surface of the blade to cause rotation.
Alternately, these machines may be classified in accordance with how the wind or fluid is directed towards the collector. At least four different groupings of this type may be formed. The first group includes those that are merely placed in a flow stream and are unable to adjust to a change in direction of the flow stream. An example of this type is U.S. Pat. No. 3,807,890 to Wright. These devices are predominantly water driven rather than wind driven since water is easily channeled and does not often change directions.
The second type relies upon an upstream funnel to direct and concentrate the flow stream. The theory being that as the funnel cross-sectional area decreases the wind speed increases to accommodate the same volume of flow. Unfortunately, most such designs do not take into account the difference existing between ambiant air pressure and the pressures found inside the funnel. Consequently, the speed and volumn of the funneled flow may be less than anticipated. Additionally, these machines direct the air flow to impinge upon a relatively small area of the collector necessitating a rather high energy exchange rate. Some typical examples of these type machines are U.S. Pat. No. 4,127,356 to Murphy, Pat. No. 4,019,828 to Bunzer, and Pat. No. 1,935,097 to Nelson.
The third type also utilizes mild funnels to capture more wind, but these machines also incorporate upstream baffles to direct the flow against a larger collector area. These machines may perhaps be slightly more efficient, but since baffling of any type removes energy from the flow stream, a higher wind speed is needed. Examples of these machines are U.S. Pat. No. 4,279,569 to Harloff and Pat. No. 1,973,509 to Santarsiero.
The fourth and last type are those that do more that simply baffle the incoming flow stream, they channel it by turning it more than ninety (90.degree. ) degrees for maximum collector impact. As can be readily expected, such channeling and drastic turning of the flow steam significatntly reduces the available energy in the flow steam. Examples of these machines are U.S. Pat. No. 4,350,900 to Baughman and Pat. No. 1,315,595 to Clark.
It is thus an object of this invention to provide an efficient means of extracting kenetic energy from the wind and transforming this energy into mechanical rotation. Another object of this invention is to provide a wind generator that directs large volume of air towards a collector yet accomplishes this task with little loss of energy. A further object of this invention is to provide a machine that automatically pivots to intercept the wind as it shifts directions. Yet another object of this invention is to provide a low cut-in threshold and a high cut-out threshold so as to convert a broader range of wind speed to mechanical energy. These and other features of this invention will become apparent upon further investigation.